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I T. L. DENNIS. I ELECTRIC LAMP. N0.306,005. Patented Sept. 30,1884.

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T. L. DENNIS.

v v ELEUTRIG LAMP. No. 306,005. vlEadzemtedl Sept. 30. 1884.-

UNITED STATES PATENT OFFICE.

THOMAS L. DENNIS, OF NEVVBURYPORT, MASSACHUSETTS, ASSIGNOR TO THECOLUMBIA ELECTRIC LIGHT AND MANUFACTURING COMPANY, OF NEW York, N. I Y.

ELECTRi C LAMP.

SPECIFICATION forming part of Letters Patent No. 306,005, datedSeptember 30, 1884.

Application filed September 26, 1883.

To all whom it may concern:

Be it known that I, THOMAS L. DENNIs, of Newburyport, in the county ofEssex and State of Massachusetts, have invented a new and usefulImprovement in Electric Lamps; and I do hereby declare that thefollowing is a full and'exact description of the same, reference beinghad to the accompanying drawings, and to the letters of reference markedthereon.

111 a prior application made by me (Serial No. 7 6,030 of 1882) I haveshown an electric lamp in which the feed is controlled by a singlemagnet in a shunt to the carbons and a resilient spring, and'to thatapplication reference is made. for the general principles in volved inthis application.

This invention is an improvement upon the invention shown in that case,the object hereof being to provide such an arrangement of devices asshall furnish an efficient and reliable starter forthe lamp when thecurrent is thrown therethrough, automatic in its action, and alsoimprove the feed of the carbons necessary upon their consumption ingiving the required light. In this case I divide the wire of the magnetinto two or more sections, with a connection between them, controlled bya lever or key contact controlled in turn by the magnet itself, so thatthe amount of wire of the coil or resistance in the magnet-circuit isautomatically adjusted to meet the requirementsof the lamp. This isfully explained hereinafter, and illustrated in the drawings, in which 1Figure 1 is a front view of the feeding devices of a lamp embodying 'myinvention, while Fig. 2 is a side view, partly in section, of the same,the carbons being in their normal inactive position; and Fig. 3, thesame with the carbons brought together to form the arc. Figs. 4 and 5are views of details of construction. Fig. 6 is a diagrammatic viewshowing the circuits in the lamp.

L L represent the upper and lower carbons, respectively-L the carbon tobe fed to compensate for waste, being'secured in the carbonholder C,while the holder of L is not shown, it, as well as the general framingof the lamp, involving no feature of the invention. The upper-carbonholder, 0, passes through suitable supports between the legs of themagnet (No model.)

tical motion thereon, this armature being kept normally away from thesepoles by any suit able springs, here typified by the springs s s, placedaround the pins 1) and between it and the poles. The carbon-holder C isformed as a tube, in the periphery of which is formed at a suitablepoint, as shown, the elongated slot 0. Within this tube is an arm orcircle, D, of slightly larger diameter than the interior diameter ofthis tube C, so that it may clamp the sides thereof when in properposition. The pivot of this arm or circle passes into and through thearmature A, and supports at one end an arm or lever, B, rigidly affixedto it, so that both E and D move together. The outer end of B carries anadj ustingscrew, Z), the end of which is arranged to take upon the topof a pin, P, projecting upwardly from the yoke Y, supporting the upperends of the magnet M M. This yoke Y'is shown in detail in Fig. 5.Fastened to the top of the magnet M M, it secures its limbs in position,is provided with a central opening, through which the holder C passes,and end openings, through which pass the poles at m. At its rear isfastened a yoke or support, 3 in which, by means of the screws y orother suitable devices, the arm or lever contact-key E is pivoted, whicharm or lever contact -key is shown in detail in Fig. 4. This lever Eshould be made of non or dia magnetic material, and is pivoted at a,above which pivot, and in the plane of the polar extensions m m, whenthe lever is in position, is the curved yoke F, of similar material, theends, however, of this yoke being faced with iron, ff, to form armaturesfor the sides of the polar extensions.

Projecting inwardly from E are the lugs H and G, as shown, each beingbeveled inwardly, as shown at h 9, between which takes the arm or pin a,attached to the rear ofthe armature A. At its lower end this arm Ecarries an electric contact, 0, made preferably as a screw, so that itmay be adjusted therein, and adaptedto take, when E is in properposition, upon thecontact 0 upon the frame of the lamp and formelectrical contact therewith. The coil of the magnet in m is made in twoor more seetions wound in the same direction, two being herein shown,distinguished for convenience by difference in the size 01" wire ofeach, although each may be of the same size wire. From the contact c aconnccti on leads directly to the inner or larger wire section. by awire, 4i, while from it a connection, 5, is made to the smaller or outersection. The wire 1 coming from the line connects with the frame of theapparatus, and with lever or arm L, and with the outer or smaller wiresection, this section being preferably of somewhat greater resistancethan the inner or larger wire section of the coil. The end 2 ot' thelarger or inner wire section has a connection, 2, to the lower carbon orits holder. The path of the circuits is shown in Fig. (5, the coils ofthe magnet M being there disassociated l'or elcarness ot'illustration,the inner or coarse or low-resistance coil being marked I O, and theouter or highresistance coil, 0 F, while Fr indicates arbitrarily the"frame of the lamp. Line 1 connects to the i'rame,while line 3 connectsto the lower carbon or its support. A connection, 4, leads from c e to IG, whence a connection, 4, is made to 3. From the frame isa connection,7, to O F, whence there is a connection, 5, to I (I. From this it willbe seen that the magnet: M, as a unit, is in a shunt to the carbons, andthat there is a shunt through I C (I) c 0 4L 2) to O F.

The operation is as follows: Normally after being trimmed, as it istechnically termed that is, the carbons L L properly placed therein,which would be at too great a distance to permit the formation of an arebetween them, and no current passing through the circuit of the lamp-thesprings s s or their equivalents force the armature A away from thepoles at 071 of M. The armature carries with it the arm 13, the weightor gravity of whose outer end causes it to turn on its pivot, and soturning to turn the arm or circle D until the ends or edges of thelatter impinge and bind upon the inner side of the tube 0, therebyholding the same in the position shown in Figs. 1 and 2-that is, withthe carbons L L too far removed to make an are effective for theproduction of light. In this condition the contact a on E is in contactwith a, so as to form a circuit, 1 E c c 4, the inner coarse coil, (I Gin Fig. 6,) 2, to line 3. It, no\v,the current be turned on, it firstpasses through this circuit, causing the coil I O to magnetize the polesin strongly, whereupon A. is attracted. As it moves down it carries thearm 13 until b strikes upon I, whereupon the movement of the outer endof 13 is arrested, its inner end, however, attached to the axis or pivotof D, continuing in motion, so that D is released from impingement with0, allowing 0 and the carbon attached thereto to tall by their gravityuntil the carbons contact or about contact. At the same time F has beenmoved so the shunt 4 I O 2 to O F and throwing O F into circuit with I0, increasing largely the resistance of the magnet circuit, which is now7 O h 5 I O 2 line 3. This increase of resist ance causes a weakening ofattractive forcein the magnet, and, owing to the resilience of thesprings, there is a slight rebound of A, causing the upper carbon, L, tobe lifted sulli ciently to form the requisite are. There is, however,suilicient magnetism in the polar extensions excrted on f f to hold E inposition to keep the connections 0 1" broken until the entire or linecircuit be absolutely broken, when E would be released and the circuitsrcstored to their original condition.

It is to be understoml that therclative length of a and the distanceapart of beveled surfaces 71 g is such that A may have some considerableplay without a impinging on either, it being necessary that A shall goto its extreme limit of motion in either direction be fore a takes uponeither. So long, then, as current flows through 1, lamp, to 3, thearmature will be held in some position intermediate ol' its extremes ofmovement and the connection c 0 remain broken, while the position of Awithin such intermediate limits will be determined by the relativeamounts of cur rent in the circuits 7 M 2 and L L, which in turn willdepend upon their relative resistances, that in L L increasing as thecarbon is consumed, more current passing through M, and calling thefeeding mechanism into opera tion. This arrangement makes an exceedingly effective starter (as it may be termed) for a single-magnet arc lamp,the magnet bcing of low resistance to start the lamp, then startingimmediately and automatically chang ing the magnet to one of highresistance, so as to throw normally through the carbons the greatestpossible percentage of the current.

Having thus described my invention, what I. claim, and desire to secureby Letters Patent, 1s

1. A magnet for controlling the feed of an electric lamp, having itscoil formed of sections wound in the same direction, in eombination withmeans controlled by its armature for forming a shunt-circuit around aportion of said coils, substantially as set forth.

2. The combination, with the magnet and its main armature, controllingthe stop or clutch mechanism of the feeding carbon-carrier, ol'a keycontrolled by said main armature and subsidiary armatures carried bysaid. key and operated on by the magnet to assist the main armature inits action upon said key, substantially as set iorth.

3. The combination of the magnet, its armature, and the key or leverprovided with the beveled surfaces arranged to be acted on by thearmature, substantially as set forth.

4-. The combination, with the magnet, of the key or lever provided withsubsidiary armatures, and with the lugs or arms arranged and adapted tobe acted 011 by the main armature of the magnet, substantially as setforth.

5. In an electric lamp, the combination. with the feeding mechanism. forcontrolling ICU ISO

the movement of the carbons, 01' a single magnet placed in ashunt-circuit to the carbons, and formed of a low-resistance section anda high-resistance section and a shunt-circuit connection, the firstsection adapted to act as a shunt to the second section when the lamp isnot in action, and means controlled by the armature oi the magnet tobreak the shuntconnection around the high-resistance section when thelamp is put in operation, and thereby increasethe resistance of theshunt-circuit containing the magnet, substantially as set forth.

6. In an electric lamp, the combination of a single magnet controllingthe feed thereof, and made in two sections coiled in the same direction,one of low resistance and one of high resistance relatively to eachother, and placed in a shunt-circuit to the carbons, an armatnre forsaid magnet, and a lever arm or key, and suitable contacts orconnections therefor, controlled by the armature, and controlling inturn the shunting out of circuit the hi gh-resistance section when thelamp is not in operation, and the throwing into circuit thereof when thelamp is in operation, so as to vary and control the relative resistancesof the carbon-circuit and the shunt-circuit through the magnet,substantially as set forth.

7. In an electric lamp, the combination of a magnet controlling the feedmechanism, made with high and low resistance sections of coil relativelyto each other, and means controlled by the armature thereof fornormally, when the circuit is not complete or is broken, shunting outthe high-resistance section and automatically breaking the shunt whilethe circuit is complete, substantially as set forth. I

S. The combination of the lever or key E, yoke F, polar extensions in m,and magnet M, substantially as set forth.

.9. The combination of the lever or key E, provided with lugs orprojections H G, having beveled faces h g, armature A, having arm or pina, and magnet M, substantially as set forth.

10. The combination of the magnet M, having coils O F and I C, the keyE, and connections 2 at 5 7, substantially as set forth.

1.1. In an electric lamp havinga single magnet controlling thefeedmechanism therefor, the magnet being made of high and low resistancesections relatively to each other, the combination of a main-linecircuit, circuitconnections therefrom through the carbons, ashunt-circuit around the carbons and through the magnet, and acircuitthrough the low-resistance section, which is a shunt circuit to thecircuit through the high-resistance section, and means for automaticallycontrolling the last-named shunt-circuit, substantially as set forth.

This specification signed and witnessed'this 25th day of September,1883.

THOMAS L. DENNIS.

\Vitn esses:

W. O. LANGAN, E. A. DICK.

